Embodiments of the present invention generally relate to systems and methods for illumination. In particular, embodiments of the present invention relate to systems, methods, and apparatus for controlled light distribution using LEDs to provide light with desirable spectral power distributions for various applications including but not limited to sports, architectural, general area, larger area and other types of lighting.
Color, correlated color temperature (CCT), and color rendering index (CRI) are important areas of concern in the lighting industry. For example, there is a desire for providing illumination which can be of a specific color or CCT, depending on the target area and desired usage of the area. Lower CCT light, in the range of 2500 to 3500K, with a greater percentage of red wavelengths in its SPD, provides a “warmer” perceived light, which is attractive and pleasing for certain occasions. However, higher CCT light in the range above 3500K, which has more blue light in its spectral power distribution (SPD), can provide better visual acuity and a better perception of brightness, making it attractive for sports lighting or other events that require a higher level of illumination.
CRI is a useful metric for comparing lighting sources as to how closely they resemble incandescent light. This provides an objective way to compare one light source to another. However, it is understood in the industry that CRI does not completely describe quality of light for a given situation. While a higher CRI generally will provide more pleasing rendering of colors, CRI does not specify which wavelengths are more or less prominent in a specific high CRI light source. This means that a given scene which has objects which are prominent in a scene and which are of a specific color (and therefore which tend to reflect certain narrow bands of the spectrum) may, depending on wavelengths emitted by the light source, have areas or objects with relatively poor color rendering, even though the light source has an overall high CRI.
Thus there is much to be gained by improving color rendition and contrast beyond what can be described by CCT and CRI.
There is also a need to increase effectiveness of lighting, not only by increasing lumen output of a light source, but also by increasing perceived brightness, since human perception of lighting quality has much to do with the acceptability and utility of lighting. Human perception of lighting is very complex, involving color perception, brightness perception, and other factors for which scientific measurement is quite difficult.
Thus there is much to be gained by improving perception of color, brightness, contrast, or other objective or subjective factors of lighting that are influenced by the complexities of metamerism and spectral power distribution.
There is therefore room for improvement in the art.